Comet 72P/Denning-Fujikawa: down but not necessarily out

It is argued that Comet 72P/Denning-Fujikawa is an old and intermittently a ctive comet evolving, at least observationally, towards a transitional mino r planet status. We have studied the fate of hypothetical meteoroids ejecte d from the comet during its two known periods of activity (1881 and 1978). A complex history of orbital evolution is found. Meteoroids ejected in 1881 first become Earth-orbit-crossing in 1960, while meteoroids ejected in 197 8 appear to hold stable, non-Earth-orbit-crossing orbits until at least 211 0. If copious amounts of meteoroids were ejected in 1881 we find some indic ation that the Earth may encounter a populous, coherent subgroup, or 'strea mlet', of them in 2009 and 2010, leading to the possibility of outburst act ivity in those years. We have investigated the possibility that the activit y of Comet 72P/Denning-Fujikawa, over the past similar to 200 years, has be en governed by impacts suffered by the comet as it moves through the main-b elt asteroid region. While encounters with centimetre-sized objects will ta ke place each time the comet orbits the Sun, the likelihood of the comet en countering a large metre-sized asteroid is essentially zero on the time-sca les considered. The outburst activity of the comet may be impact-modulated in the sense that small-object impacts might trigger the explosive release of gases trapped in subsurface cavities.